1.2 IC issues ?????

screename

I only have one IC for two sets of speakers. I was moving the IC between speakers and found that my 1.2's make SDA when the opposite speaker (1.2tl) is connected, but not when the 1.2's are connected to each other.

The 1.2tl sda drivers working fine with the IC between the 1.2tl's, but not when using the IC between the 1.2's.

To clarify: Both 1.2's work when connected to the opposing 1.2tl but not when connected to each other.

Any insight is appreciated.

[Deleted User]

Hello,
Let me make sure I understand you correctly. You have a pair of SDA SRS 1.2 and there's no sound coming from the SDA components when using the correct SDA interconnect cable connected, correct? This is a twin/blade cable, correct?
Regards, Ken

DarqueKnight

If he has the 1.2 and 1.2TL, the cable has to be pin/blade. The original SRS was blade/blade.

Screename, has there been any crossover modifications or binding post upgrades done on your speakers?

screename

It is Pin blade for both pairs. Thanks both of you for the responses.

Ken, I am the guy that bought the 16 replacement tweets from you a month or so ago.

I don't believe there have been any mods to the speakers as they seem bone stock and very "original" and clean I might add. The guy I purchased them from didn't report anything either.

Whats odd about it is that when I connect the oposing TL speaker with either one of the 1.2's the 1.2 and the TL SDA drivers seem to work fine. This is also the case when the TL's are connected to each other.

The problem is when the 1.2's are connected to each other: NO SDA?

I'm stumped and not sure where to begin to troubleshoot the problem.

Thanks again for your assistance.

dorokusai

EDIT: A case of mistaken identity.

You can't troubleshoot a speaker with another different speaker, regardless of it being the same "type".

The condition you are creating, by using a 1.2 and 1.2TL, doesn't really mean anything.

Good luck Ken.

F1nut

Well, ya gotta start somewhere! Open them up and take a look inside for loose connections.

screename

No offence Doro, but I think you have me confused. I never requested anyone's assistance re: an IC issue. F1 and I had a nice debate about two pairs of SDA's side by side but that was it.

I will open them up and have a look for wires and report back, just seems odd that they are firing with the TL's connected and not each other.

danger boy

well yous problem sounds similar to mine. when i hooked up my SRS i swear on my mothers good name that the left SDA drivers were not working. they were moving. but only because of the air being moved by the stereo drivers in the left cabinent only. the right SDA, all speakers were firing like they should.

WHen i disconnected the blade/blade connector i didn't get any sound from the left SDA tower at all. The problem ended up being a bad interconnect RCA cable. replaced cable and both left and right SRS's worked like a charm again. I think the SRS, and maybe all SDA's are kind of picky when it comes to good stable connections.

Recently the speaker wires from one of the SRS to and amp was loose, and it really affected the signal quality of the sound. The SDA speaker was cutting in and out. I refastened the wires.. and everything is good again.

So you may want to replace the RCA interconnect from your amp to pre amp. if you're using a seperate amp.
good luck.

dorokusai

screename wrote:

No offence Doro, but I think you have me confused. I never requested anyone's assistance re: an IC issue. F1 and I had a nice debate about two pairs of SDA's side by side but that was it.

I will open them up and have a look for wires and report back, just seems odd that they are firing with the TL's connected and not each other.

Oh ok, well there you go, sorry There are a bunch of us that have schematics, just start by opening them up as suggested above. If you have a fax, I can send you the wiring diagrams.

[Deleted User]

Hello Screen,
There can be a few reasons you're not hearing anything from the SDA components of both speakers. It's not surprising you hear SDA information when each speaker is connected to another SDA model. The SDA information, heard in the right channel, is produced by the left channel's crossover. So, when you connect another SDA speaker its crossover is producing the SDA signal which is being heard by the opposite channel speaker. We have to figure out what is not going on inside each speaker. There is a general purpose check out sheet that is always the first step in evaluating any SDA speaker. If you can give me your US Mail address at kswauger@polkaudio.com I can send you the check out sheet. This is the first step to determining what might be going on.
Regards, Ken

hoosier21

Kenneth Swauger wrote:

Hello Screen,
There is a general purpose check out sheet that is always the first step in evaluating any SDA speaker.

Any chance Polk could pdf this type of material and have it somewhere on this site?

screename

Thanks for all the input, I will open them up tonight and report back my findings.

Kind regards,


Brad

screename

I got the check out sheets today. While going through the testing process I found a set of wires that had been mislabled ( + for - ). That took care of the sda drivers not working in the 1.2's. I am quite please it was so simple.

During the testing process I noticed that the sda speakers were much stronger on the TL's versus the 1.2's. When I tested the levels between the right and left channels, it was clearly apparent that the SDA drivers were working in the TL's but when I checked them with the 1.2's they could be heard but not to the degree that I could hear from the TL's. I had to put my ear to them to hear when doing the balance left and right test on the 1.2's.

My question then; would the crossovers changed this much from the 1.2 to the TL's to hear such a differance between them? or is the a crossover issue with my 1.2's?

I believe the differance would be very apparent to a seasoned SDA listener, my ears are just not trained to that degree yet.

Thanks again for your input,

and Ken thanks very much for the instructions.

F1nut

You've still got a problem with the 1.2's. The SDA drivers should play at about the same level as the stereo drivers.

screename

I got ahold of a meter today and tested the resistance as laid out in the test sheets. The results are in one of the attachments.

So to me it would seem that the pos. and neg. are reversed.

I remember when first looking at these two sets of speakers that the positive and negs were opposite. 1.2's versus TL's

Here's a few pics to show the differances.

I thought maybe I had reversed the red and black nuts when I bi-wired but they were put back on as the pictures show they should.

Are they connected backwards internally?
Would that make the SDA's speakers not as loud as they should be?

screename

Bump

[Deleted User]

Hello Screename,
There are two measurements that are suspect. The IC pin 1 to black and the IC pin 2 to red. These are the opposite of what they should be. I would reverse the two connections that go onto the IC connector. Black to IC pin 1 should be 0 Ohms and IC pin 1 to red should be around 3 to 4 Ohms. Let me know what you find when you make these changes.
Regards, Ken

sda2mike

I thought the SDA speakers were SUPPOSED to be much quieter, than the regulars?? If not, then I gots probs, too

[Deleted User]

Hello,
Also, your IC pin 2 to red measurements are a little low. These drivers have a green wire to their negative terminals and a blue wire to their positive terminals. If one of the drivers is wired incorrectly that could account for the low reading. Let me know what you find.
Regards, Ken

screename

So I pulled the post caps and as you can see in the pictures these are still glued in place as they came from Polk, or so I would assume.

Next question is, what would be the best way to swap the to IC wires as you can see the connections are very differant.

I have to wonder if the connections were made incorrectly since '88?

I have not changed the tweeters out in thes speakers yet, so I am assuming that they are still factory connections as well.

S!#% happens as far as the connections go, I just can't imagine going 17 years without figuring it out.

screename

So I got to taking apart the speaker today to see WTF. As it turns out the label on the back of my 1.2's is actually an SDA-SRS label, not a 1.2 label.

See my post from last night to see the two labels.

Why Polk decided to reverse the + and - when they came out with the 1.2's and eventually the TL's is anyone's guess.

This is what prompted my inspection further into the speaker. SDA drivers were 6511's as they should be and everything inside said 1.2 as it should be with a pin-blade interconnect.

When all the levels came back last night in the opposite value, I was with Ken thinking the IC had somehow gotten reversed, but this was not the case. It was the inputs that were reversed due to the label on the back of the speaker being incorrect.

I feel for the guy that had these for all those years and never got to hear the true SDA sound.


The less volume out of the SDA Drivers was the result of the speaker posts being reversed, so if your sda drivers are not as loud when balance testing, check the posts and eventually where they connect to the crossover as it's labeled + and - because the label on the speaker could be wrong as it was in my case.

I would be very interesed in hearing from anyone that finds this issue with theirs.

Thanks to Ken and all who gave advice, my 1.2's thank you too.

Kind Regards,



Brad

danger boy

congrats on solving the problem. big difference in sound huh?